UpdateDeutschland presents a valuable empirical case for studying the transition from massive civic participation to persistent public value in an open digital living lab. There are over 4400 participants, 581 proposals, 330 initiatives within the programme, around 70 initiatives in operation after the opening phase, 30 selected initiatives, 14 collaborations between public and civic sectors, and 9 collaboration initiatives. These levels are not regarded as equal but rather as different layers of evidence. There are four approaches employed in the study: Configurational Stress-Conversion Analysis, Open Funnel Retention Analysis, Role-Weighted Evidence Balance, and Mandate-Carrier Coupling. The funnel reveals that deep comparative evidence issues involve 0.20% of the conservative participant population, and that the interview layer includes more representatives from public managers and organizers and commentators, compared to the whole archive. Calibration at the case level results in the identification of three patterns: compressed cases, learning-reservoir cases, and carrier-capable cases. The primary finding here is that durable public value does not emerge through openness, ideation, or prototyping alone. Durable public value emerges when adaptive participation is linked with mandate anchoring, ownership, artefact maturation, and continuance vehicle. Thus, the current paper interprets UpdateDeutschland as stress-conversion process in which collaborative energy turns into public value provided it is evidenced, authorized, owned, and carried out of the lab.